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The number of n-node binary trees fixed by the corresponding automorphism(s).
Table of n, a(n) for n=0..20.
A. Karttunen, C-program for computing the initial terms of this sequence
Sequence in context: A180019 A112801 A173862 * A096323 A035682 A054543
Adjacent sequences: A089870 A089871 A089872 * A089874 A089875 A089876
Antti Karttunen, Nov 29 2003